1. Field of the Invention
The invention relates to an angle indicating apparatus, more particularly to an angle indicating apparatus for use with a table saw and capable of positioning at predetermined angles.
2. Description of the Related Art
When cutting a work piece using a table saw, an angle indicating apparatus is employed to indicate the cutting angle and to position the work piece on the table saw.
Referring to FIG. 1, a conventional angle indicating apparatus 10 is shown to include a rod member 12, an indicia member 11, an indicator 13, and a locking unit 14.
The rod member 12 is slidably received in a slide groove of a table saw (not shown) such that the angle indicating apparatus 10 can be positioned on and is slidable relative to the table saw.
The indicia member 11 is mounted pivotally on the rod member 12 about a pivot axis, and includes a base plate 112 and a stop block 111 extending uprightly from one end of the base plate 112. The stop block 111 is used to abut against the work piece to be cut by the table saw. The base plate 112 is formed with a curved guide slot 113 having a curvature centered at the pivot axis. The base plate 112 further has a top side provided with angle indicia 114 that are disposed radially and outwardly of the guide slot 113 with respect to the pivot axis.
The indicator 13 is mounted on one end of the rod member 12, and has a pointing end 131 pointing to the angle indicia 114.
The locking unit 14 includes a handle body 141 and a threaded shank (not visible) extending from the handle body 141 and through the guide slot 113 so as to threadedly engage the rod member 12 and arrest undesired rotation of the indicia member 11 relative to the rod member 12.
In the conventional angle indicating apparatus 10, the indicia member 11 is allowed to rotate to any arbitrary angle due to the lack of a positioning mechanism. Therefore, when aligning the indicator 13 with a particular angle on the angle indicia 114, a few more micro-tuning steps are needed for final angle positioning. As such, the angle positioning procedure in the conventional angle indicating apparatus 10 is slow and troublesome. In view of the fact that a work piece is generally required to be cut at some standard angle, such as 30, 45 and 60 degrees, there is evidently a need for a simple angle positioning procedure.
To overcome the aforesaid drawback, another conventional angle indicating apparatus 20 has been proposed heretofore, as shown in FIG. 2. The conventional angle indicating apparatus 20 includes a rod member 22 and an indicia member 21. The indicia member 21 has angle indicia 211 and a plurality of protruding blocks 23 that extend from a periphery of the indicia member 21 and that are angularly spaced apart at predetermined angles. Each protruding block 23 has a positioning screw 231 mounted thereon. An indicator 24 is mounted on one end of the rod member 22, and has a pointing end pointing to the angle indicia 211. A stop plate 25 is mounted pivotally on one side of the indicator 24. The stop plate 25 is used to abut against one of the positioning screws 231 so as to quickly position the indicia member 21 at one of predetermined angles relative to the rod member 22. To move the indicia member 21 to another one of the predetermined angles, the stop plate 25 is pivoted to allow the adjacent protruding block 23 to pass through the indicator 24. After rotating the indicia member 21 to the desired one of the predetermined angles, the stop plate 25 is again pivoted to abut against the adjacent positioning screw 231. At this time, the locking unit 26 can be operated so as to threadedly engage the rod member 22 and arrest undesired rotation of the indicia member 21 relative the rod member 22.
Although the aforesaid angle indicating apparatus 20 provides the function of positioning the indicia member 21 at predetermined angles, the following drawbacks are encountered:
1) The pivoting operations of the stop plate 25 are awkward to conduct. Also, since the protruding blocks 23 with the positioning screws 231 mounted thereon take up a lot of space, the number of the protruding blocks 23 that can be installed is severely limited, thereby limiting the corresponding number of the predetermined angles.
2) The abutting force applied to the positioning screws 231 by the stop block 25 will result in angular misalignment in the long run. Therefore, the positioning screws 231 need to be periodically adjusted to ensure accuracy.
3) Because the indicator 24 and the protruding blocks 23 are disposed on the outer periphery of the indicia member 21, not only will there be inconvenience during operation, the user will also be prone to injury due to the sharp edges of the aforesaid components.
Therefore, the main object of the present invention is to provide an angle indicating apparatus that can overcome the aforesaid drawbacks of the prior art.
Accordingly, the angle indicating apparatus of the present invention includes a rod member, an indicia member, an indicator, a spring-loaded tumbler unit, and a locking unit.
The indicia member is mounted pivotally on the rod member about a pivot axis, and includes a base plate and a stop block extending uprightly from one end of the base plate. The base plate is formed with a generally semi-circular cutout having a straight edge that is proximate to said one end of the base plate, and a curved edge that is connected to the straight edge and that has a curvature centered at the pivot axis. The base plate has a top side provided with angle indicia that are disposed adjacent to the curved edge of the cutout. The base plate is further formed with a curved guide slot that is disposed radially and outwardly of the curved edge of the cutout with respect to the pivot axis. The base plate further has a bottom side disposed on top of the rod member and formed with a plurality of angularly spaced apart positioning grooves. The positioning grooves correspond respectively to the predetermined angles and are spaced apart at equal radial distances from the pivot axis.
The indicator is mounted on the rod member, is disposed in the cutout, and has a pointing end pointing to the angle indicia.
The spring-loaded tumbler unit is mounted on the rod member and engages removably a selected one of the positioning grooves in the bottom side of the base plate.
The locking unit passes through the guide slot and is operable so as to engage the rod member in order to arrest undesired rotation of the indicia member relative to the rod member.